- An estimated 15 thoroughbreds die on American racetracks every week
- Those that survive may be auctioned to slaughterhouses or euthanized
- Animal welfare activists are pushing for federal regulation of the horse racing industry
Temecula, California (CNN) -- The horse's name is Nitro Active. He was bred for speed.
This great-great-grandson of the legendary Secretariat had won nearly $200,000 in prize money at tracks around Southern California. It had been a modestly successful racing career, but by December of last year it was over.
The coulda, woulda, shoulda Triple Crown winners
Nitro Active was breaking down. Because of injuries to his tendons and leg joints Nitro Active could barely stand, let alone race.
No more racing for "I'll Have Another" 
I'll Have Another Injures leg, retires His fate seemed clear. Like many spent and injured racehorses, Nitro Active was destined for euthanasia or a Mexican slaughterhouse supplying horse meat to restaurants in Europe and Japan. He sold at auction for $190.
Injury sidelines 'I'll Have Another' from Belmont
It was at that point that Monika Kerber came into Nitro Active's life. Kerber runs Villa Chardonnay, a horse rescue operation in Temecula, California.
"He deserves another chance," said Kerber.
Most days, he would simply lay in his stall, in pain and misery, Kerber said. After months of expensive veterinary care, today Nitro Active is slowly healing. But for hundreds of other racehorses, there is no happy ending.
"They are literally running for their lives," said Nancy Perry of the American Society for the Prevention of Cruelty to Animals, or ASPCA. "If they run too fast they break down on the track and die. And if they don't run fast enough, they are discarded."
The Jockey Club -- the registry for thoroughbred horses in the United States, Canada and Puerto Rico -- estimates that 15 thoroughbreds die on American racetracks every week. Those figures do not include other breeds of horses that also race in the United States.
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Undercover video shows horse abuse "When you extrapolate that to quarter-horse racing and standardbred racing, you realize the numbers are astronomical," Perry said.
The ASPCA is pushing for federal regulation to halt the use of performance enhancing drugs on the racetrack.
"They are injecting cocaine. They are injecting cancer drugs into horses in order to mask pain," said Perry. "They are even injecting snake venom."
She said the proposed Interstate Horse Racing Improvement Act would remove oversight from a hodgepodge of seemingly ineffective state commissions.
As the sun rises above Santa Anita Race Track in Arcadia, California, the horses take to the track. This was the location where Nitro Active spent most of his racing career. There is an air of calm and peace at this racing oval at the foot of the San Gabriel mountains. But racetrack CEO Mark Verge knows that his sport is under pressure.
"Horse racing on its own has too much infighting," Verge said. "Everyone is looking up and saying, 'The public doesn't even care about us anymore.'"
But Verge bristles at charges that his sport mistreats horses.
"The last thing you want to do is bring families and friends (to the track) and have a horse break down," Verge said.
He also stressed that the industry has raised millions of dollars to provide a comfortable retirement for aging racehorses.
In recent years, Santa Anita has spent millions more installing an artificial race surface in an effort to reduce racing injuries. But Verge said the new surface didn't work. There were constant problems keeping the track in proper condition to race. While mortality rates during races were lowered, trainers complained that the new surface was causing an increase in training injuries.
The artificial surface has since been replaced by a traditional dirt track. Racehorse fatalities at Santa Anita are back up, the highest in the state. In addition to racing incidents, three horses were killed during the filming of horse race scenes at Santa Anita for the HBO TV series, "Luck."
Attendance at racetracks nationwide is falling.
That's why federal regulation is needed, according to the ASPCA. Perry said the sport could regain its popularity if people believed it was cleaning up its act.
"In sports where people compete, we have prohibitions on the use of steroids and other performance enhancing drugs," she said. "But for some reason we've allowed horse racing to slip through the cracks."
Some of racing's greatest horses have met horrific fates. In 2008, Eight Belles snapped both front legs in the Kentucky Derby and was euthanized in front of a TV audience of millions. Two years earlier, Kentucky Derby winner Barbaro broke his leg racing in the Preakness Stakes. In 2002, the horse racing world was rocked by the news that 1986 Kentucky Derby winner Ferdinand was apparently killed in a Japanese slaughterhouse.
Nancy Perry, ASPCA
Industry groups said $35 million a year is spent on equine drug testing. They said the problem is being blown out of proportion, but some in horse racing want state racing groups to agree to uniform medication standards as a way of controlling what violations do exist.
Horse racing's critics said these and other deaths are not isolated tragedies, but rather part of a callous pattern within the inner world of the racing industry.
Veterinarian Wayne McNeel has been guiding Nitro Active back along the long road to recovery. The horse's future is still far from certain. But he said he hopes that one day soon Nitro Active will be able to bear a rider around the shaded grounds of his new home.
